b = {
    'zero': 0,
    'one': 1,
    'two': 2,
    'three': 3,
    'four': 4,
    'five': 5,
    'six': 6,
    'seven': 7,
    'eight': 8,
    'nine': 9
}

a = [101, 103, 107, 109, 113,
    127,	131,	137,	139,	149,	151,
    157,	163,	167,	173,	179,	181,
    191,	193,	197,	199,	211,	223,
    227,	229,	233,	239,	241,	251,
    257,	263,	269,	271,	277,	281,
    283,	293,	307,	311,	313,	317,
    331,	337,	347,	349,	353,	359,
    367,	373,	379,	383,	389,	397,
    401,	409,	419,	421,	431,	433,
    439,	443,	449,	457,	461,	463,
    467,	479,	487,	491,	499,	503,
    509,	521,	523,	541,	547,	557,
    563,	569,	571,	577,	587,	593,
    599,	601,	607,	613,	617,	619,
    631,	641,	643,	647,	653,	659,
    661,	673,	677,	683,	691,	701,
    709,	719,	727,	733,	739,	743,
    751,	757,	761,	769,	773,	787,
    797,	809,	811,	821,	823,	827,
    829,	839,	853,	857,	859,	863,
    877,	881,	883,	887,	907,	911,
    919,	929,	937,	941,	947,	953,
    967,	971,	977,	983,	991,	997,
]


g = 0
asas = 0
check = False
c = input().split()

if c[0] in b and c[0] != 'zero' and c[1] in b and c[2] in b and len(c) == 3:
    en = int(str(b[c[0]]) + str(b[c[1]]) + str(b[c[2]]))
    p = en
    m = en
    if en in a:
        print(en)
    while p not in a:
        p += 1
        g += 1
    while m not in a:
        m -= 1
        asas += 1
    if g < asas:
        print(p)
    else:
        print(m)
else:
    print('Wrong input')
